The present invention relates generally to pattern dyeing of textile material such as carpet. More particularly, the invention relates to pattern dyeing of continuously moving textile materials by the use of spray jets.
The dyeing of textile webs such as carpet is well known in the art, and is carried out by a variety of techniques. One common technique, for example, uses a roller and doctor blade arrangement whereby dye is picked from a trough by the roller which then transfers the dye to a doctor blade. The dye falls off the lower end of the inclined doctor blade whereupon it may contact a textile web moving perpendicular to the axis of rotation of the roller.
The following patents are representative of known roller and doctor blade textile dyeing arrangements:
______________________________________ Pat. No. Inventor(s) Issue Date ______________________________________ 3,964,860 Leifeld June 22, 1976 4,170,958 Moser Oct. 16, 1979 4,202,188 Gruber May 13, 1980 4,267,712 Gruber May 19, 1981 ______________________________________
The Leifeld patent discloses a textile dyeing method and apparatus which may use a series of oscillating interruptor blades to interrupt the dye to be deposited on the carpet. The dye may be interrupted by the interrupting blades in a varying manner on the roller or on the doctor blade to result in strips of dye being deposited on the carpet in a random fashion. In an alternate embodiment, a plurality of oscillating air jets are used to interrupt dye flow on an inclined plate.
The Moser patent discloses a roller and doctor blade arrangement wherein a plurality of air outlets are arranged in a rotating tube positioned above the doctor blade to allow its air flow to rearrange the dye film on the doctor blade. Alternately, the rotating air outlet tube may be disposed beyond the lower end of the inclined doctor blade to selectively blow dye into a dye reservoir as its drops from the blade instead of allowing it to drop onto the moving textile web.
The Gruber '188 patent discloses a textile dyeing apparatus having a roller and docltor blade arrangement wherein dye dropping off a doctor blade in a shroud is blown outward by a series of axially spaced spray jets to cause non-uniform application of the dye. The spray jets move during operation of the dyeing process in order to randomize the pattern on the carpet.
The Gruber '712 patent shows a textile dyeing apparatus having a roller and doctor blade arrangement wherein dye on the doctor blade is interrupted by a number of wiping elements attached to a rotating tube.
Recently, it has been proposed to print textile fabrics, including pile carpets, by the programmed spraying or jetting of plural colored dyes onto the surface of the moving fabric. Typical of such processes and apparatus, in addition to the aforenoted applications, are the process and apparatus described in U.S. Pat. Nos. 3,443,878; 3,570,275; 3,969,779 and 4,034,854; and British Pat. No. 978,452. Generally, such apparatus consists of a plurality of dye applicator bars or manifolds spaced along the direction of movement of the textile material and each containing multiple dye nozzles or jets extending transversely across the moving material. Each jet may be activated by suitable electric, pneumatic, or mechanical means to dispense dye onto the moving material, and pattern control to apply the dyes in a desired sequence may be accomplished by various conventional programming devices, such as mechanical cams and drums, coded punch tapes, magnetic tapes, computers and the like.
U.S. Pat. Nos. 3,443,878 and 3,570,275 also disclose specific means for applying jets of dyes to print a fabric by use of continuously flowing dye streams which are deflected by a stream of air or a mechanical deflector to permit impingement of the dye stream upon the fabric or recirculation to a dye supply reservoir.
It can be appreciated that in the pattern dyeing of pile fabrics, such as carpets and the like, it is highly desirable to be able to achieve very detailed, sharp, and intricate patterns such as are obtained by conventional weaving processes employing multiple colors of yarns and control of the individual yarns to form the pattern, e.g. an Axminster or Wilton weaving process. Therefore, in the pattern dyeing of pile fabrics utilizing plural streams of dye which are selectively applied to the moving fabric to pattern the same, it is extremely important in such highly porous materials to accurately locate the dye in accurate amounts in the pile yarns of the fabric. For example, to achieve by pattern dyeing the definition which can be obtained by the aforementioned weaving processes, it is desirable that the dye applied be in small enough amounts as to dye a single yarn or tuft, or equivalent area, without undesirably wicking or migrating into adjacent tufts of the pile surface. Obviously then, accuracy of amount and placement of dye in the pile fabric becomes extremely important in dyeing pile fabrics intricate patterns.
It can be appreciated that certain factors can detrimentally influence accurate positioning of the dyes in the pile fabric. The speed of movement of the fabric must be carefully correlated to the application of the dyes. If the carpet speed varies with respect to the time of application of the dyes, inaccuracies in placement obviously occur. Similarly, if the flow rate of the dye varies with respect to the movement of the carpet to which it is applied, undesirable shading and inaccurate placement problems result. Thus, applying the exact amount of dye to the exact spot on the carpet, e.g., enough dye to dye the full length of a single tuft of yarn, is a much sought for goal in pattern dyeing of carpets.
U.S. Pat. Nos. 3,969,779 and 4,034,854 represent an attempt to minimize problems resulting from variations in the speed of the fabric or the flow rate of the dye during application of the dye streams.
The apparatus of the '779 and '854 patents include a jet pattern dyeing machine having a plurality of gun bars each containing plural dye jets extending across the width of an endless conveyor. The gun bars are spaced along the conveyor, and textile materials are carried by the conveyor past the gun bars where dyes are applied to form a pattern thereon. The application of dye from the individual dye jets in the gun bars is controlled by suitably adapted pattern control means. The amount of dye applied to the pile fabric is controlled by application of the streams in repeating increments of dye, wherein all of the continuously flowing streams in a given gun bar are deflected simultaneously by an air jet at repeating intervals of time throughout the dyeing operation to apply the dye in discrete incremental spots or "shots", to the pile fabric. In this manner, a given area of the fabrics is dyed by repeated, intermittent applications of dye to the pile, instead of an uninterrupted continuous flowing stream of dye over the area and the dye blown away is collected. The '854 patent includes electromagnetically operated valves for controlling the flow of deflecting air.
Although the prior art systems have proven to be a useful a useful tool to carpet stylists and manufacturers, they have been subject to one or more of a number of disadvantages. Prior art systems wherein dye is applied from troughs using rollers and doctor blades for transfer of dye to the carpet usually do not produce patterns with great resolution. It is extremely difficult to change the pattern produced by such prior art devices because of their reliance on mechanical positioning and movement of a scraper blade or spray jet. In order to change the pattern, access must be gained to the mechanical supporting arrangement to reposition the scraper blade or the air jet. Where the pattern is provided by a rotating air tube, the apparatus is limited to one pattern unless the air tube itself is changed or a number of the openings in the air tube are plugged, either procedure being somewhat cumbersome and time consuming.
Prior art systems which avoid reliance upon a roller and doctor blade arrangement, such as the aforenoted programmed spray or jet dyeing systems produce a finer and more desirable resolution pattern; however, they are disadvantageous in other respects. For example, they often require a separate dye recirculation reservoir whereby dye which is deflected by the air jet may be retrieved.
Moreover, the use of air jets to break up or blow away falling dye streams may atomize the dye and cause the dye to be deflected beyond the reservoir. This loss of dye is not only costly, but any atomization of the dye may cause the dye mist to enter the air. Final setting of the dye may be in undesirable locations. Additionally, the atomized mist may create health problems to subjected machine operators to breathe dye contaminated air. Special precautions must be taken to avoid this condition. Additionaly, prior art devices are not generally designed to improve existing systems, but rather require complete replacement. A manufacturer having millions invested in a continuous line system employing troughs and rollers for dye application will generally want to improve his current machines, instead of scrapping his capital investments in his current system. Thus, since many patentable improvements are unsuited for use with prior art systems, they are not readily available, for economic reasons, to manufacturers employing conventional dyeing systems.